Is there a way to save all settings of the sequence editor to disk and load them when needed?
Sequence Editor belongs to the scene.
The settings shown are on data that belongs to each scene. A new scene will use blender's defaults.
Python console. Create a sequence editor in the context scene. It is of type bpy.types.SequenceEditor.  The value for overlay_frame is shown
&gt;&gt;&gt; sed = C.scene.sequence_editor_create()
&gt;&gt;&gt; type(sed)
&lt;class 'bpy.types.SequenceEditor'&gt;

&gt;&gt;&gt; sed.overlay_frame
0

.
To have the same settings in another scene, would suggest creating a new and copying the attributes of the old, or copying the scene and unlinking from it unrequired data, including strips. Be a good candidate for an operator with presets.
Alternatively save it as a scene in another blend and  append the scene each time instead of  creating a new one.
Another option would be to save a workspace template or startup file with the settings desired.